BEIRUT— Syrian Kurdish fighters have captured more territory from Islamist rebels in northeastern Syria, a Kurdish militant group said on Monday, tightening their grip on an area where they have been setting up autonomous rule.

The Kurds said they had routed their rivals in three days of battles, while Islamist sources spoke of a tactical retreat.

Syria, tugged by various regional conflicts, has frayed into a patchwork of warring ethnic and sectarian pockets, tilting the balance of power in some of its Middle Eastern neighbors.

Kurdish assertiveness has posed a quandary for Ankara as it tries to make peace on its own soil with militants from the Kurdistan Workers Party (PKK), a rebel group which has fought for greater Kurdish autonomy in Turkey for three decades.

Turkey fears a power grab by Kurdish militias in Syria may embolden the PKK militants. But it is also uneasy about swaths of territory on its border falling to al-Qaida-linked rebels.

Redur Xelil, spokesman for the armed wing of the Syrian Kurdish Democratic Union Party (PYD), said Kurdish militias had seized the city of Ras al-Ain and all its surrounding villages.

Ras al-Ain is in Syria's northeastern province of Hasakah bordering Iraq and Turkey. Its population is 70 percent Kurdish and 30 percent Arab.

The Syrian Observatory for Human Rights, a monitoring group, said the Kurds had seized at least 19 towns in the area.

Majority Sunni Arab Muslims have led the revolt against President Bashar al-Assad, in which Kurds have played an ambivalent role, but rebels are also fighting among themselves.

Islamist militants have clashed with more moderate groups in mostly rebel-held northern Syria, and have battled Kurds in northeastern border areas for months.

Xelil said the latest Kurdish advance had followed fierce fighting in the past three days. “This was not a retreat, they [the Islamists] were defeated,” he told Reuters by telephone.

“We did this because they were a direct threat to Kurdish regions. There were daily attacks from their side.”

A source linked to the al-Qaida-affiliated Nusra Front said the Islamists had withdrawn without a fight, citing problems in convincing enough militant units to stay on the frontline.

The Islamists are falling back to Tel Abyad, another northern town bordering Turkey, and rebel sources reported clashes with the Kurds in that area as well.

Xelil said Kurdish fighters would press on to Tel Abyad.

“As long as they are there they are still threatening our areas. We will retake all the territory between Tel Abyad and Ras al-Ain,” he said.

Turkish officials say they have had meetings with Syrian Kurdish groups, expressing willingness to work with them if they remain opposed to Assad, promise not to seek autonomy through violence or before Syria's wider conflict is resolved, and pose no threat to Turkey's own security.

Manned deep space missions are still a long way off, but space agencies are already testing procedures, equipment and human stamina for operations in extreme environment conditions. Small groups of astronauts take turns in spending days in an underwater lab, off Florida’s southern coast, simulating future missions to some remote world. VOA’s George Putic reports.

Video

Manned deep space missions are still a long way off, but space agencies are already testing procedures, equipment and human stamina for operations in extreme environment conditions. Small groups of astronauts take turns in spending days in an underwater lab, off Florida’s southern coast, simulating future missions to some remote world. VOA’s George Putic reports.

Video

Fifty years ago, lawmakers approved, and U.S. President Lyndon Johnson signed, the Voting Rights Act of 1965. The measure outlawed racial discrimination in voting, giving millions of blacks in many parts of the southern United States federal enforcement of the right to vote. Correspondent Chris Simkins introduces us to some civil rights leaders who were on the front lines in the struggle for voting rights.

Video

Billions of dollars of so-called ‘dirty money’ from the proceeds of crime - especially from Russia - are being laundered through the London property market, according to anti-corruption activists. As Henry Ridgwell reports from the British capital, the government has pledged to crack down on the practice.

Video

Ottawa, Illinois, is the hometown of W.D. Boyce, who founded the Boy Scouts of America in 1910. In Ottawa, where Scouting remains an important part of the legacy of the community, the end of the organization's ban on openly gay adult leaders was seen as inevitable. VOA's Kane Farabaugh reports.

Video

Artificial limbs, including the most complex of them – the human hand – are getting more life-like and useful due to constant advances in tiny hydraulic, pneumatic and electric motors called actuators. But now, as VOA’s George Putic reports, scientists in Germany say the future of the prosthetic hand may lie not in motors but in wires that can ‘remember’ their shape.

Video

A British pro-democracy group has accused Russia of abusing the global law enforcement agency Interpol by requesting the arrest and extradition of political opponents. A new report by the group notes such requests can mean the accused are unable to travel and are often unable to open bank accounts. VOA's Henry Ridgwell reports.

Video

Talks on a major new trade agreement among 12 Pacific Rim nations are said to be nearing completion in Hawaii. Some trade experts say the "positive atmosphere" at the discussions could mean a deal is within reach, but there is still hard bargaining to be done over many issues and products, including U.S. drugs and Japanese rice. VOA's Jim Randle reports.

Video

Earth is in the midst of its sixth mass extinction. The last such event was caused by an asteroid 66 million years ago. It killed off the dinosaurs and practically everything else. So scientists are in a race against time to classify the estimated 11 million species alive today. So far only 2 million are described by science, and researchers are worried many will disappear before they even have a name. VOA’s Rosanne Skirble reports.

Video

Scientists have long been trying to develop an effective protection and cure for malaria - one of the deadliest diseases that affects people in tropical areas, especially children. As the World Health Organization announces plans to begin clinical trials of a promising new vaccine, scientists in South Africa report that they too are at an important threshold. George Putic reports, they are testing a compound that could be a single-dose cure for malaria.

Video

The latest issue of 'New York' magazine features 35 women who say they were drugged and raped by film and television celebrity Bill Cosby. The women are aged from 44 to 80 and come from different walks of life and races. The magazine interviewed each of them separately, but Zlatica Hoke reports their stories are similar.

Video

The United States is promising not to give up its fight against what Secretary of State John Kerry calls the “scourge” of modern slavery. Officials released the country’s annual human trafficking report Monday – a report that’s being met with some criticism. VOA’s National Security correspondent Jeff Seldin has more from the State Department.

Video

Abandoned more than 50 years ago, the underground streetcar station in Washington D.C.’s historic DuPont Circle district is about to be reborn. The plan calls for turning the spacious underground platforms - once meant to be a transportation hub, - into a unique space for art exhibitions, presentations, concerts and even a film set. Roman Mamonov has more from beneath the streets of the U.S. capital. Joy Wagner narrates his report.

Video

Greece has replaced Italy as the main gateway for migrants into Europe, with more than 100,000 arrivals in the first six months of 2015. Many want to move further into Europe and escape Greece’s economic crisis, but they face widespread dangers on the journey overland through the Balkans. VOA's Henry Ridgwell reports.

Video

After the closure of a major rubbish dump a week ago, the streets of Beirut are filling up with trash. Having failed to draw up a plan B, politicians are struggling to deal with the problem. John Owens has more for VOA from Beirut.

Video

A U.N. climate conference in December aims to produce an ambitious agreement to fight heat-trapping greenhouse gases. But many local governments are not waiting, and have drafted their own climate action plans. That’s the case with Paris — which is getting special attention, since it’s hosting the climate summit. Lisa Bryant takes a look for VOA at the transformation of the French capital into an eco-city.